(Not Applicable)
(Not Applicable)
The present invention generally relates to electro-therapy devices and more particularly to a portable multi-function electro-therapy device which uses a microprocessor to generate and control output signals.
The therapeutic use of electricity (also known as electro-therapy) is known. Electricity can be used, for example, to reduce pain (U.S. Pat. No. 4,887,603 issued to Morawitz et al.) or for treating edema, muscle spasms, and sprains (U.S. Pat. No. 5,010,896 issued to Westbrook). There are a variety of forms of electrical therapy as described more fully below.
Transcutaneous Electrical Nerve Stimulation (TENS) generates electrical impulses that are sent through electrodes placed over nerve centers. The various pulses employed by TENS can block pain signals normally sent to the brain through nerve fibers, thereby interrupting the brain""s awareness of pain. TENS can be used to activate the release of endorphins which are used by the body to suppress pain naturally. TENS car be used for chronic pain (e.g., arthritis or low-back pain) and/or acute pain (e.g., childbirth, traumatic injury or surgery).
A type of electrical therapy used for tissue repair and edema reduction is High Voltage Pulsed Current (HVPC) or High Voltage Pulsed Galvanic (HVPG) therapy which uses a device to provide short duration low amperage high voltage pulses to preselected areas of a patient""s tissues through electrical leads or electrodes.
Neuro-Muscular Electrical Stimulation (NMES) uses the same technology as TENS to cause a muscle to xe2x80x9ctwitchxe2x80x9d or contract on purpose. NMES is used for muscular therapy (e.g. for muscle tension, stiffness in joints or back areas, to increase motion from disuse or atrophy or for increasing blood circulation). NMES output current is usually stronger and has a wider pulse width than TENS.
Another type of electrical therapy is Inferential (IF) therapy which differs from TENS and NMES in that it delivers concentrated stimulation deep into the affected tissue. IF therapy exploits the interference of two separately generated sinusoidal currents applied to the body simultaneously.
Interferential stimulators have two standard nodes of operation. The first mode produces two different: output frequencies on two separate output channels that are applied to a patient using four electrodes. The two signals are applied to that patient and allowed to add together at a targeted location on the patient. The second mode takes the same two frequencies, adds them together inside the device and then applies a single channel of stimulation to the patient via two electrodes.
There are clinical devices that perform various types of electrical therapy (such as those described above). However, it is often difficult for a patient to take the time needed to travel to a clinical facility in order to get proper treatment using clinical devices. Portable or handheld devices were developed to overcome the inconvenience required for proper treatment using clinical devices. A typical handheld device performs one type of therapy (e.g., TENS, NMES or IF therapy). Typically, if a patient requires different types of treatment, the patient either has to travel and use a clinical device or purchase multiple portable devices.
Recently, portable devices have been developed which provide more than one type of electrical therapy. For example, there are devices which include both HVPC and NMES electro-therapy (U.S. Pat. No. 5,514,165 issued to Malaugh et al. and U.S. Pat. No. 6,064,911 issued to Wingrove). Though more flexible than single mode devices, these multi-function devices are still limited. For example, multi-function electro-therapy devices do not include IF therapy. Typical handheld IF stimulators create the frequencies through the use of two separate oscillator circuits. One oscillator has a fixed frequency and the other oscillator is controlled by varying either a capacitor""s value or a resistor""s value in the oscillator circuit. Additional circuitry is used to add the two frequencies together to form the pre-modulated IF waveform. This method of pulse generation generally requires a large number of components and a considerable amount of test and calibration time which increases production costs and decreases reliability. A microprocessor can also be used to either control the two different oscillators or to generate the two required frequencies. To operate in the proper range of frequencies with the proper resolution a very fast and often expensive microprocessor is required. Thus, handheld or portable devices have not used microprocessors to generate frequencies due to prohibitive costs.
Thus, a need exists for a portable electrical therapy device which can perform IF therapy, as well as other types of electro-therapy. In addition, the device should use technology which allows for the device to be produced in a manner which increases reliability without increasing costs.
The present invention is directed to a system and method for performing electro-therapy. The invention is a multi-mode portable electro-therapy device which comprises a microprocessor located in a housing. The microprocessor generates and controls output signals. The device also includes a display, at least one keypad, an electrode jack and at least one pair of electrodes connected to the electro-therapy device via the electrode jack. Output signals are transmitted to a patient via the electrodes.
In accordance with other aspects of the invention, the multiple modes of the device comprise an interferential mode, a pre-modulated interferential mode, a neuromuscular mode and a high volt pulse current mode. The output signal may be generated by combining two signals, for example when in interferential mode. The two signals may be started at different times.
In accordance with still other aspects of the invention, the output current may be a constant output voltage or a variable load. The output current may be monitored. R variable load current may be adjusted based on the monitored output. The monitored output may be stored. The stored monitored output may be used for later evaluation, for example to determine skin resistance. The output signal can be modified based on a change in voltage. For example, as battery power decreases, the output signal can be modified so that the output signal remains constant.
In accordance with yet other aspects of the invention, new modes can be created by combining existing modes. For example, one mode may automatically follow another mode.
In accordance with further aspects of the invention, the output signal comprises a duty cycle. The output signal can be varied by changing the duty cycle.
In accordance with yet other aspects of the invention, available functions are based on the user. For example, a patient can modify the amplitude of a signal being output. However, a medical professional, such as a doctor, can perform functions, such as defining modes, which cannot be performed by a patient.
In accordance with still other aspects of the invention, a calibration device may be connected to the electro-therapy device via the electrode jack. An external device, such as a computer, may also be connected to the electro-therapy device via the electrode jack. Data is transmitted to the external device via the electrode jack for processing. For example, stored monitored data can be viewed and/or analyzed.
In accordance with other aspects of the invention, output signals are generated using a microprocessor (i.e., the signals are generated using software). The method employed by the electro-therapy device performs the following steps: (1) accepts inputs for defining at least one mode of therapy; (2) determines the mode of electro-therapy; (3) uses a microprocessor to calculate at least one output signal based on the mode of therapy; (4) transmits the at least one output signal to at least one pair of electrodes; and (5) monitors for a change in mode. The above steps (3-5) are repeated until the transmission of the output signal is terminated (e.g., end of therapy, device turned off).
In accordance with still other aspects of the invention, the electro-therapy device may be calibrated. For example, calibration may occur when the device is turned on. Preferably, additional calibration functions can be performed upon request.
In accordance with yet other aspects of the invention, output may be monitored and stored. Signals may be adjusted based on the monitored output.